1. Field of the Invention
The invention relates to internal combustion engines and, in particular, to rotary internal combustion engines driven by the sequential combustion of combustible fuel in a plurality of internal combustion chambers.
2. Description of the Related Art
A considerable amount of research in rotary cycles was done in the 1920""s and 1930""s. Many types of rotary cycles were considered. The development lead to the most famous of rotary engines, namely the Wankel engine. Many mechanical problems were solved during that time. However, even though the rotary cycle is superior to the Otto cycle in all theoretical thermodynamic calculations, only one large series automobile, i.e., the Mazda RX-7, utilizes the Wankel cycle.
The instantly proposed system deviates considerably from the Wankel system, most notably in the differences regarding compression. A certain amount of teaching may nevertheless be transferred, for instance seal and spark plug placement information.
Most prior art rotary engines utilize the rotor to compress the fuel/air mixture directly in the combustion chamber. The rotor is thereby radially asymmetric, it is mounted eccentrically relative to the rotor chamber, or the chamber is not circular. Examples of such engines are found in U.S. Pat. No. 4,075,981 to Durst, U.S. Pat. No. 3,301,233 to Dotto et al., and U.S. Pat. No. 3,782,110 to Kobayashi, respectively. An alternative design was recently proposed in U.S. Pat. No. 5,429,084 to Cherry et al. where the rotor and the chamber are radially symmetrical and the combustion chambers are instead formed laterally on either sides of the rotor and several vanes move axially to close off the combustion chambers. The compression xe2x80x9cstrokexe2x80x9d is effected by the narrowing of the combustion chamber during the angular displacement of rotor relative to the rotor housing (the stator) and the reduction in chamber volume effected by the respective vane.
As noted above, the rotary cycle is superior to the Otto cycle on paper. In reality, however, Otto cycle engines are quite principally better in terms of thermodynamic efficiency. Whether or not this has anything to do with the fact that much more research has been invested in the Otto cycle as compared to the rotary cycle cannot be easily answered. It should be possible, however, to improve a rotary engine further so that its actual efficiency approaches the theoretical limits more closely.
It is accordingly an object of the invention to provide a rotary internal combustion engine, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which is generally improved in its efficiency.
With the foregoing and other objects in view there is provided, in accordance with the invention, a rotary internal combustion engine, comprising:
a stator defining a rotor housing with a cylindrical inner wall surface, a rotor rotatably supported in said housing about a rotor axis, said rotor having a cylindrical peripheral surface rotating equidistantly from said inner wall surface of said stator;
a plurality of vanes projecting substantially radially from said peripheral surface of said rotor and sealing against said inner wall surface of said stator;
a plurality of turning valves equi-angularly distributed about a periphery of said housing chamber, said turning valves sealing against said peripheral surface of said rotor and, while allowing a respective one of said vanes to pass by, sealing against the respective said vane.
In accordance with an added feature of the invention, each of said turning valves rotate about an axis extending parallel to said rotor axis and coinciding with said inner wall surface of said rotor housing.
In accordance with an additional feature of the invention, said plurality of vanes are a number at least one higher than a number of said plurality of turning valves.
Preferably, a ratio of vanes to turning valves is from 1 to 2, in particular 8:5. The latter ratio has been found to lead to a particularly smooth cycle. The ratio may be varied widely, however, in dependence on the output requirements of the system.
In accordance with the invention there is also provided an improved internal combustion engine of the type having a plurality of cylinders and a plurality of reciprocating pistons disposed in said cylinders, said pistons sequentially performing selective strokes including a power stroke and an exhaust stroke. The improvement comprises: a compression system disposed externally of the cylinders for compressing a fuel/air mixture and for injecting the compressed fuel/air mixture into the cylinders following an exhaust stroke of the respective piston.
In accordance with yet another feature of the invention, the compression system includes a pressure vessel for storing a fuel/air mixture and a line communicating with each of the cylinders for injecting the fuel/air mixture into the cylinders.
In accordance with a concomitant feature of the invention, the compression system is a variable pressure system allowing injection of a compressed fuel/air mixture at varying pressure.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a rotary internal combustion engine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.